Optical Data Transmission Apparatus Using Polarization Multiplexing
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Solution Overview
Problem
Existing optical data transmission apparatuses face challenges in achieving stable high-speed communication, particularly with mobile units, due to complex assembly processes and limited directivity, which restricts communication range and speed beyond 10 Mbps, and are prone to interference and astigmatic differences.
Innovation Solution
The apparatus employs a first and second communication unit with a laser diode emitting single-mode light, a multi-mode optical fiber to convert the signal, and polarization elements to manage polarization directions differently, eliminating the need for precise alignment and reducing astigmatic differences, allowing for stable high-speed communication over varying distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a laser diode emitting single-mode light with specific polarization direction is used, then communication speed can be improved beyond 10 Mbps, but precise alignment between the laser diode and polarization element becomes difficult to achieve
Solution Approach 1:
The patent introduces a polarization-maintaining optical fiber as an intermediary component between the laser diode and the polarization element. This optical fiber has specific polarization characteristics that automatically maintain the polarization state of the transmitted light, serving as a mediator that eliminates the need for precise alignment between the laser diode and the polarization element, thereby resolving the contradiction between achieving high communication speed and maintaining manufacturing precision
Solution Approach 2:
The patent changes the parameter of the optical transmission medium by using a polarization-maintaining optical fiber with specific birefringence characteristics. This parameter change in the optical fiber allows it to maintain the polarization state of light over the transmission distance, thereby enabling high-speed communication without requiring precise alignment during assembly
2Adaptability or versatility
If communication units are made mobile to improve adaptability, then versatility is improved, but signal interference and reception stability deteriorate
Solution Approach 1:
The patent applies local quality by using polarization division multiplexing, where different polarization states (horizontal and vertical) are used to carry different signals. This allows two communication units to communicate simultaneously on the same frequency without interfering with each other, even when mobile, thereby maintaining both versatility and signal reception stability
Solution Approach 2:
The patent segments the communication signal into two separate polarization components (horizontal and vertical polarization). Each component carries independent information, allowing the system to transmit multiple signals simultaneously through the same physical medium without interference, thus enabling mobile communication while maintaining reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration simplifies the assembly process, enhances communication stability and speed, and maintains performance even when units move relative to each other, ensuring reliable full-duplex communication without the need for precise mechanical adjustments.
Implementation Method 1
a light emitting unit provided with a laser diode for emitting single-mode light
Implementation Method 2
an optical lens for condensing the optical signal output from the multi-mode optical fiber into parallel light
Implementation Method 3
a first polarization element for passing the optical signal polarized in a first direction out of optical signals output from the optical lens
Data Source
AI summary
An optical data transmission apparatus is provided, in which a first communication unit 101 and a second communication unit 102 arranged to freely move relatively to each other each include an optical signal transmission unit having a laser diode 120 for emitting single-mode light, a multi-mode optical fiber 111 for guiding a single-mode optical signal output from the laser diode 120 , converting the single-mode optical signal into a multi-mode optical signal, and outputting the multi-mode optical signal, an optical lens 112 for forming the optical signal output from the multi-mode optical fiber 111 into parallel light, and a first polarization element for passing the optical signal polarized in a predetermined direction out of optical signals output from the optical lens 112.